Crossbar switch with prestressed mobile contact spring and perpendicular first and second shifting means

ABSTRACT

Shown is a cross-point mechanism for a crossbar switch in which each cross-point includes one or more mobile rigid wire springs conductors extending normal to a stationary conductor, there being one stationary conductor for each mobile wire spring. Two adjacent notches are inset in a stationary support insulator for each mobile spring, one for holding the mobile spring in the released or unoperated condition and the other for holding the mobile spring in the operated condition in contact with a stationary conductor. Each wire is permanently flexed toward the notches so that on movement toward the switch-operated condition the spring is moved orthogonally past a shoulder separating the notches and released there for movement due to the spring flexure. For release of the cross-point connection, the mobile spring is translated in the direction normal to the alignment of the adjacent notches to free the spring of the shoulder and allow it to restore to the unoperated condition or release condition due to the spring flexure. The mobile spring is moved in operating condition by first and second perpendicular shifting means. Actuation of said first and second shifting means moves said mobile spring into a ready position, and then release of said first shifting means allows said spring flexure to move the mobile spring into the operated position.

United States Patent Grundig 1541 CROSSBAR swl'rcn WITH PRESTRESSED MOBILE CONTACT SPRING'AND PERPENDICULAR FIRST AND SECOND SHIFTING MEANS [72] Inventor: Heinz Georg Grundlg, Am Erlanger, Germany International Standard Electric Corporatlon, New York, NY. 7

221 Filed: Apr. 29, mo 1211 Appl. 116.; 32,1313

[73] Assignee:

[52] U.S.CI. "200/176, 335/1 1 1, 335/113 1511 1111. 01. v ltllh67/l4 581 FieldolSearch ..200/l75,l76,l77,l78; ass/109,111, 112, 113

[56] mm Cited UNITED STATES PATENTS 3,529,113 9/1970 Vazquezetal. .200/175 7 3,396,257 8/1968 Vazquez .200/166 as 3,360,626 12/1967 Vazquez "200/115 ux some: PATENTS 0R APPLICATIONS- 1,160,450 8/1969 Great Britain ..2oo/177 l,l57,768 7/l969 GreatBritain ..200/l75 1151 13,643,053 [451 Feb. 15, 1912 Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorney-C. Cornell Remsen, Jr., Walter J. Baum, Paul W. l-lemminger, Charles L. Johnson, Jr., Delbert P. Warner,

1 James 8. Men and Marvin M. Chaban [571 ABSTRACT Shown is a cross-point mechanism for a crossbar switch in which each cross point includes one or more mobile rigid wire springs conductors extending normal to a stationary conduc- -tor, there being one stationary conductor for each mobile wire spring. Two adjacent notches are inset in a stationary support insulator for each mobile spring, one for holding the mobile spring in the released or unoperated condition and the other for holding the mobile spring in the operated condition in contact with a stationary conductor. Each wire is permanently flexed toward the notches so that on movement toward the switch-operated condition the spring is moved orthogonally past a shoulder separating the notches and released there for V movement due to the spring flexure.

Fori'elease of the cross-point connection, the mobile spring is translated in the direction normal to the alignment of the adjacent notches to free the spring of the shoulder and allow it to restore to the unoperated condition or release condition due to the spring flexure. The mobile spring is moved in operating condition by first and second perpendicular shifting means. Actuationof said first and second shiffing means moves said mobile spring into a ready position, and then release of said first shifting means allows said spring flexure to move the mobile spring into the operated position.

6 Claims, 1 1 Drawing Figures PATENTEDFEB 1 5 B12 3. 643 OS 3 SHEET 3 0F 6 PATENTEDFEB 15 I972 3, 643 O53 SHEET 8 [IF 6 CROSSBAR SWITCH WITH PRESTRESSED MOBILE CONTACT SPRING AND PERPENDICULAR FIRST AND SECOND SHIFTING MEANS BACKGROUND OF THE INVENTION In the telecommunication field, particularly in automatic telephony, modern switching systems often use coordinate connection networks including an important number of Crossbar switches generally arranged in equipments called multiswitch frames. In such equipments, the establishment of a cross-point brings into play a selection bar, a connection bar, a middle piece or selecting finger, a set of mobile contact springs mechanically integral one with the other by means of an insulating guide and a set of fixed contacts.

Now, techniques evolution and technologic improvements have changed the design of switching systems. The latter tend either to a full electronification or to a semielectronification in which multiswitches are used to constitute the speech network and are connected to electronic control circuits.

In the latter case, it is necessary that the multiswitch characteristics and performances be compatible with those of the electronic equipments and circuits associated with them, which means that their operating speed needs to be increased and their bulk reduced.

Of course, there have been trials to reduce the dimensions of standard multiswitches, but this reduction only concerned the dimensions of the components and not the very conception of the operating principle so that this reduction could not be optimal.

Besides the standard multiswitch units necessitate numerous adjustments and tests before and after their putting into service, which raises significant cost price, labor, servicing and maintenance problems.

In order to avoid these drawbacks the applicant has already designed a miniature multiswitch of new conception, not necessitating any middle pieces and particular adjustment. Such a multiswitch is described in U.S. Pat. Nos. 3,360,626 issued l2/26/67 and 3,55 l ,63l issued 12/29/70 both to Charles Vazquez and assigned to the assignee hereof.

SUMMARY OF THE INVENTION It is the object of the invention to provide a new and improved cross-point structure for a crossbar switch.

It is a further object of the invention to provide a new crossbar switch cross-point in which the moving contact is permanently biased toward its operated position.

It is a still further object of the invention to provide a new and improved crossbar switch cross-point in which the moving contact is permanently biased toward its released position.

BRIEF DESCRIPTION OF THE DRAWINGS Various further features will be disclosed from the following description which is given by way of nonlimited example and with reference to the accompanying drawings which represent:

FIG. 1, a perspective view, partly cutaway, of the main parts of a known type of a multiswitch;

FIG. 2, a perspective view, partially cutaway of the main parts constituting a multiswitch according to the invention;

FIG. 3, a schematic sectional view taken along the axis A A of FIG. 2;

FIGS. 4 to 8, schematic plan views explaining the operation of the multiswitch in FIG. 2;

FIG. 9, a perspective view, partially cutaway of the main parts of another embodiment of the multiswitch;

FIG. 10, a schematic sectional view taken along the axis B- B of FIG. 9;

FIG. 11, a schematic plan view explaining the operation of the multiswitch in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT The description will be started by referring first to FIG. 1 in which the electrical connection to be established must be carried out between a mobile contact element such as I or 2 and a fixed contact element such as 3. A support is constituted by a printed circuit plate 4 which bears conducting configurations 5. These configurationsor wirings-enable the establishment of appropriate connections between the soldering terminal areas such as 6, and certain pins of the plate plugin part (nonrepresented in the figure) which ensures the connection with the external circuits. The plate is used as direct support of the mobile contact elements-or springs-l or 2. These springs are constituted by a metal wire of circular section and of good electrical conductivity comprising two rectilinear parts on both sides of a median part wound as a hunting horn" in order to form several close-wound turns 7. Such an arrangement offers the advantage of allowing the use of very short springs having nevertheless an elasticity similar to that of longer springs. One extremity of the mobile spring 1 (or 2) is captive of the plate 4 and connected by a blob of solder to the soldering terminal area 6 of an appropriate printed circuit 5. The other extremity is free; however, the anchoring in plate 4 is such that the springs l (or 2) may have a certain inclination relative to the vertical axis, this arrangement giving them a determined rest position in one angle of the selection bar windows as it can be seen more particularly with the spring 2.

The free end of each mobile spring traverses three superposed openings respectively made in three different pieces, that is the connection bar 8, the selection bar 9 and the support 10 of the fixed springs. Each piece is located in its plane proper which is parallel to the planes of the two other pieces. Besides, if the support 10, like the plate 4 is all in one block, it is obvious that other connection and selection bars are arranged in a same plane and parallel to the connection bar 8 and the selection bar 9. The number of these control bars is determined by the multiswitch equipment and by the number of cross-points to be established. It is to be noted that this arrangement has been described in detail in the already mentioned US. Pat. No. 3,551,631.

Each connection bar 8 has openings 11 comprising a tooth 12, the selection bars 9 being provided with windows 13 and 14 arranged by pairs. The distance that separates openings 11, as well as the pitch of the pairs of windows 13 and 14 are so intended that, after mounting of the sets of control bars 8 and 9, these openings and said windows be superposed.

The support 10 includes grooves 15 whose pitch depends upon that of the opening 13 and 14. These grooves serve to house the fixed contact elements-or springs-3 whose turn pitch is defined by the diameter of the mobile spring 1 or 2 such that the latter can engage and establish a contact between two adjacent turns.

The support 10 also includes as many openings 16 as there are mobile springs. These openings open on the grooves I5 so that they enable both the travel of the upper part of the mobile springs and the establishment of a contact between this part and the turns of the fixed spring 3.

The operation of such a multiswitch will be briefly explained; a more detailed description will be found in the above-mentioned U.S. patents. When the selection bar 9 is operated in the direction of the arrow F1, the windows 13 and 14 each drive a mobile spring 2 until the latter is in front of the tooth 12 of the corresponding connection bar. At that time, the connection bar 8' is moved in the direction of the arrow F2: a tooth l2 acts upon each operated spring 2 which results in driving them and in particular, in bringing the active part of the free end of these springs into contact with two turns of the corresponding springs 3. An electrical connection is therefore established between two fixed springs 3 connected to external circuits by appropriate means and two mobile springs 2 also connected to other external circuits through the printed circuits 5.

Now will be described the embodiment shown in FIG. 2 in which are found the same components: the plate support 4, the printed circuits 5 and the soldering terminal areas 6 used for the connection of the mobile springs such as 17, 18, 19. The fixed spring support includes openings-as represented in the figure-for each pair of mobile springs 17 and 18. These openings are constituted by four notches, 21, 22, 23, 24, two for each mobile spring which then has a notch corresponding to its rest positionor rest notch 21 (or 23) and a notch corresponding to its operating position-or operating notch 22 (or 24). The fixed contacts are good electricity conductor metal wires embedded in the support material so that they traverse the bottom of the notches 22 and 24 of the openings having the same alignment. The visible part 25 or 26 of these wires may be covered with a precious metal in order to ensure a better electric contact.

The selection bars 27 present notches such as 28 and 29 the cutaway of which determines a tooth 30, each notch being provided to cooperate with a mobile springs 17 or 18. The connection bars-such as 31have also a T shape, each cutaway made on the left or on the right of the vertical of this T being provided in order to act upon a spring 17 or 18.

It is to be noted that the mobile springs 17, 18, or 19 are strongly cambered which confers them an important force in the direction of the camber and wedges them, for example, in the rest position in the bottom ofthe notch 21 or 23 as it can be seen with the spring 19. This force is such that, when the mobile spring 19 is in the operating notch 24 it comes, by its own, into contact with the corresponding fixed contact 26 while exerting a pressure on it. These details are better illustrated in FIG. 3 which represents a schematic sectional view along the axis A-A of FIG. 2, the selection and connection bars not being represented. It can been seen, on the right, a mobile spring 19 in its rest position, therefore strongly bent, and, on the left, a mobile spring 19 in its operating position against a fixed spring 16, its camber corresponding to be exerted contact pressure.

Now will be described the operation of this multiswitch referring to FIGS. 4 to 8. In the latter, the outline of an opening of the support 20 has been represented by a fine line, the selection bar, by a thick line and the connection bar bya dotted line.

FIG. 4 corresponds to the rest condition: due to their camber, the springs 32 and 33 lean in the left angle of the rest notches 21 and 23 and the fixed contacts 25 and 26 are free. The selection and connection bars are respectively urged in the direction of the arrows F3 and F4 by nonrepresented restoring springs.

In FIG. 5, the connection bar electromagnet has just received a current impulse which causes the displacement of this bar in the direction of the arrow F5 and the driving of the two mobile springs 32 and 33. It will be noted that the spring 32 slides along the side 34 of the rest notch while the spring 33 slides first along the edge 35 of its rest notch then along the tooth 30 of the selection bar 27.

The connection bar being held in this position, a current impulse is applied to the control electromagnet of the selection bar 27. The latter moves in the direction of the arrow F6 (see FIG. 6) and, therefor, drives the mobile springs 32 and 33- the spring 33 by the tooth 30, the spring 32 by the edge 36 of the left notch of the selection baruntil they are at the level of the operating notches.

In FIG. 7, the selection bar 27 is held in its operating position shown in FIG. 6 while the impulse which has driven the connection bar 31 has ceased. The latter thus returns into the rest position (that is shown in FIG. I) under the action of its restoring spring in the direction of the arrow F4. The mobile springs 32 and 33, urged in the direction of the arrow F7 due to their camber, engage their operating notch as the bar 31 moves back until they abut against the fixed contacts 25 and 26, thereby establishing the required connection. At this time, the function of the selection bar 27 is finished and it returns into its rest position under the action of a restoring spring in the direction of the arrow F3.

When the connection is to be released, the connection bar 31 is operated anew in the direction of the arrow F5 (FIG. 8). The edges 37 and 38 of this bar act upon the corresponding mobile springs 32 and 33. At the time they pass the extremity of the tooth 39separating the rest notch from the operating one, the bar 31 stops moving in the direction of the arrow F5 and returns into its rest position in the direction of the arrow F4. The mobile springs 32 and 33 slide along the bevelled part of the teeth 39 and as the bar 31 moves back, they describe a trajectory shown by the dotted arrows until they return to their initial position in the rest notch angle.

The multiswitch shown in FIG. 9 also uses the mobile spring elastic deformation and response principle embodied by the FIGS. 2 to 8. However, this time, as it can be seen more particularly in FIG. 10 which is a schematic sectional view along the axis B-B of the FIG. 9, the springs such as 40, in the rest position, are almost unbent and their position is due to the preferable inclination given when mounting them on the printed circuit plate 4. On the opposite, the operating position is such that the mobile springs such as 41 are bent which ensures them the necessary contact pressure.

Referring to FIG. 9, there can be found the plate 4 of printed circuits 5 to which are associated the mobile springs 42, 43, 44. The selection bars 45 have cutaways similar to those of FIG. 2 and the function of the teeth 46 is identical to that of the teeth 30 (FIGS. 2 to 8). The connection bars 56 include windows such as 47 and 48 enabling, for example, the springs 42 and 43 to be driven.

The fixed contact support 49 comprises openingsas indicated in the figure-for each pair of mobile springs. These openings are constituted by four notches 50, 51, 52, 53, two for each mobile spring which therefore has a rest notch 51 (or 53) and an operating notch 50 (or 52). The fixed contacts are constituted by a precious metal coating laid in the bottom of the operating notches such as 50 and 52. This coating is metal connected with a semiterminal area 54 (see also FIG. 11) which is part of a printed circuit 55. It will be noted that the active extremity of the mobile springs may also be coated with a precious metal in order to improve the electric characteristics of the connection established with the fixed contact.

Now will be briefly described the operation of such a multiswitch referring to FIGS. 9 and 11, the function of the control bar notches and windows being similar to that described with FIGS. 4 to 8.

When the connection bar 56 is operated in the direction of the arrow F8, its windows 47 and 48 drive the mobile springs 42 and 43 in the direction of the arrows F9 (FIG. 11). Then, the appropriate selection bar 45 is operated in its turn in the direction of the arrow F10 (FIG. 9) so that the teeth 46 drive the mobile springs 42 and 43 in the direction of the arrows F11 (FIG. 11) until they are facing the operating notches 50 and 52. At this time, the connection bar 56 moves in the opposite direction; the mobile springs then slide along the edge of the teeth 46 of the selection bar in the direction of the arrow F12 due to their elasticity and finally come to abut against the metal coating 57 of the operating notches 50 and 52.

To release the connection, the connection bar 56 is operated anew in the direction of the arrow F8, which results in the sliding of the mobile contacts 42 and 43 along the coating 57 in the direction opposite to the arrow F12 (FIG. 11). When the mobile springs pass the extremity of the tooth, the connection bar 56 moves in the opposite direction so that the mobile springs return to their rest position at the bottom of the notches 51 and 53; indeed, the elastic stress to which are submitted the mobile contacts in the operating position results in a force torque, the resultant of which indicated by the arrow F13 tends permanently to restore the springs into their theoretical rest position referenced 42' and 43' in FIG. 11.

While there has been described what is at present thought to be the preferred embodiment of the invention, it is understood that further modifications may be made therein and it is intended to claim in the appended claims all such modifications which fall within the true spirit and scope of the invention.

What is claimed is:

l. A crossbar switch comprising a plurality of rectangularly disposed alignments intersecting at a plurality of cross-points, each of said cross-points including (a) a mobile, contact-bearing spring element, (b) a stationary contactor, and (c) a stationary support member including a set of first and second aligned notches with a stationary contactor at a wall in the second notch; each spring element flexed toward an at rest state in the first notch, first spring element shifting means operative to displace the spring elements of one alignment to an intermediate position free of said first notches of said one alignment, second spring element shifting means operative to displace spring elements in an alignment normal to said one alignment and thereby move any spring elements from the intermediate position to a ready position aligned with the second notch of a set, wall means on said second shifting means positioned to guide any spring elements at said ready position into said second notch under the spring element fiex on restoration of said first shifting means to close the crosspoint contact to the contactor in a spring element operated state.

2. A switch as claimed in claim 1, wherein there are means for anchoring one end of each spring element to'position the contact to enter into one or the other of said notches, and wherein at each cross-point the end wall of said stationary contact-bearing notch is closer to the projection of said spring element from its anchoring means than the first notch whereby to increase the pressure of the contact on the stationary contactor in the operated state. i

3. In a switch as claimed in claim 2, said stationary contactors of said switchcomprise conductive rods mounted transversely in said support member adjacent an alignment of cross-point notches and open to the contact in the second notch of each set and means for insulating each of said rods within the first notches to prevent contact therein between the rod within the first notch and the spring element.

4. A switch as claimed in claim 2, wherein said stationary contactors each comprise a printed circuit contactor forming an electrical contact at the end wall of the second notch.

5. A switch as claimed in claim 1, wherein the spring'elements are flexed in a direction angularly disposed to both said rectangular alignments to hold any spring elements in the state to which moved.

6. A switch as claimed in claim 5, wherein there are wall means on said first shifting means for moving any operated spring element to a second intermediate position on reoperation of said first shifting means with said second shifting means restored, and guide means on said first notches to guide any spring from said second intermediate position to the at rest state under said spring element flexure. 

1. A crossbar switch comprising a plurality of rectangularly disposed alignments intersecting at a plurality of cross-points, each of said cross-points including (a) a mobile, contact-bearing spring element, (b) a stationary contactor, and (c) a stationary support member including a set of first and second aligned notches with a stationary contactor at a wall in the second notch; each spring element flexed toward an at rest state in the first notch, first spring element shifting means operative to displace the spring elements of one alignment to an intermediate position free of said first notches of said one alignment, second spring element shifting means operative to displace spring elements in an alignment normal to said one alignment and thereby move any spring elements from the intermediate position to a ready position aligned with the second notch of a set, wall means on said second shifting means positioned to guide any spring elements at said ready position into said second notch under the spring element flex on restoration of said first shifting means to close the cross-point contact to the contactor in a spring element operated state.
 2. A switch as claimed in claim 1, wherein there are means for anchoring one end of each spring element to position the contact to enter into one or the other of said notches, and wherein at each cross-point the end wall of saiD stationary contact-bearing notch is closer to the projection of said spring element from its anchoring means than the first notch whereby to increase the pressure of the contact on the stationary contactor in the operated state.
 3. In a switch as claimed in claim 2, said stationary contactors of said switch comprise conductive rods mounted transversely in said support member adjacent an alignment of cross-point notches and open to the contact in the second notch of each set and means for insulating each of said rods within the first notches to prevent contact therein between the rod within the first notch and the spring element.
 4. A switch as claimed in claim 2, wherein said stationary contactors each comprise a printed circuit contactor forming an electrical contact at the end wall of the second notch.
 5. A switch as claimed in claim 1, wherein the spring elements are flexed in a direction angularly disposed to both said rectangular alignments to hold any spring elements in the state to which moved.
 6. A switch as claimed in claim 5, wherein there are wall means on said first shifting means for moving any operated spring element to a second intermediate position on reoperation of said first shifting means with said second shifting means restored, and guide means on said first notches to guide any spring from said second intermediate position to the at rest state under said spring element flexure. 